IMHO that will increase 1) your workload tenfold because domains change rapidly, producing a result that is as 2) useful as listing all remote IP's that tried to crack your SSH the last five years and which is as 3) good for Netfilter performance as sugar is in the tank of your car. Check out
http://www.surbl.org/lists.html for "multi.surbl.org" and
http://opdb.berlios.de/.
If you want strict ACL's equivalent to
an authoritarian system of government under absolute control of a single person maybe forcing all traffic through a proxy and adding an allowed sites list is easier to set up and maintain.
